A known support bearing of this type and its function are illustrated in FIG. 4 and FIG. 5. FIG. 4 shows the design of a known support bearing 30 and FIG. 5 shows the function of the known support bearing 30.
FIG. 4 shows a schematic cross section through the known support bearing 30, and the support bearing 30 is realized rotationally symmetrical to a strut axis 31 such that only one half of the support bearing 30 is visible in FIG. 4. One end 4 of a strut element 5 that forms a vibration damper 21 in this case is surrounded by an annular metallic body 39 in the form of an inner ring that cooperates with an annular rubber bearing 3. The annular rubber bearing 3 features at least one elastic rubber element 20 and a rubber bearing housing 8, wherein the end 4 of the strut element 5 protrudes into a center 23 of the metallic body 39. The rubber bearing 3 introduces lateral and longitudinal forces of the strut element 5 into the car body 7. For this purpose, the rubber bearing 3 features an inflexible and rigid rubber bearing housing 8 with a rotationally symmetrical shoulder 18 flanged thereon.
A first ball bearing race 11 is fixed on this shoulder 18 of the rubber bearing housing 8. A second ball bearing race 19 of the ball bearing 9, in contrast, is rotatable relative to the shoulder 18 and the rubber bearing housing 8. This rotatable second ball bearing race 19 carries one end 13 of a spring element 10 in the form of a coil spring 16. In addition, one end 25 of a bellows 24 that protects the strut element 5 from contamination is non-positively clamped between the end 13 of the spring element 10 and the second ball bearing race 19.
In this known configuration of a support bearing 30, the strut element 5 forms the piston rod of the vibration damper 21. The vibration damper 21 is fixed on the car body 7 such that it is prevented from turning by means of the rubber bearing 3, the shoulder 18 of the rubber bearing housing 8 and another elastic rubber element 40 in this known embodiment of a support bearing 30. This support bearing 30 consequently has the disadvantage that the strut element 5 and the rubber bearing 3 cannot be turned relative to the car body and the coil spring 16 turns about the rubber bearing housing 8 during a steering maneuver due to the ball bearing 9 such that only the torsional movements of the coil spring 16 of the coil strut are compensated by the ball bearing 9.
FIG. 5 shows a schematic diagram of the function of such a known support bearing 30 according to FIG. 4, in which the rubber bearing 3 cannot be turned relative to the car body 7. The double arrow Q in FIG. 5 indicates that the support bearing 30 should have a high transverse rigidity (Q) in the transverse direction. The support bearing 30 should have a lesser rigidity in the longitudinal direction as indicated with the arrows (L) in order to improve the traveling comfort in the longitudinal direction.
In this context, the term transverse direction refers to the direction extending transverse to the driving direction of the vehicle and the term longitudinal direction refers to the direction extending in the driving direction of the vehicle, and the driving direction is indicated by the position of the front wheel 32 in FIG. 5. In order to realize this different rigidity, the rubber bearing 3 contains recesses 14 and 15 that weaken the rubber bearing 3 in the longitudinal direction (L). Such rigidity-reducing recesses are not provided in the transverse direction.
A known support bearing 30 of this type has the disadvantage that the rubber bearing 3 of the support bearing 30 maintains its position when a front wheel 32 is turned into a curve position 33 such that the rigidity in the direction of the arrow (K) is significantly reduced in comparison with the transverse rigidity (Q) and a greater liability must be accepted while driving through a curve, in which the front wheel 32 is turned into the curve position 33.
In a MacPherson front axle with struts 6, it is not only disadvantageous that the rigidity decreases while driving through curves, but the strut element 5 and the center 23 of the support bearing also are respectively aligned with the center of rotation of an axle pin of the front wheel 32 such that rotating seals must be accepted.
In view of the foregoing, it is desirable to develop a support bearing that at least reduces and preferably substantially eliminates the disadvantages of the state of the art and ensures that little or no reduction of the transverse rigidity occurs. It should furthermore be ensured that no rotating seals are required while driving through curves, particularly in pneumatic struts such as, for example, on a MacPherson front axle. In addition, other desirable features and characteristics will become apparent from the subsequent summary and detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.